New hybrid materials based on poly(ethyleneoxide)- grafted polysilazane by hydrosilylation and their anti-fouling activities

Abstract The objective of this work was to develop new coating materials based on poly(ethyleneoxide) (PEO), which was grafted onto polysilazane (PSZ) by hydrosilylation. Three types of PEO with different molecular weights (350, 750, 2000 g/mol) were studied. The kinetics and yields of this reaction have been surveyed by 1 H and 13 C NMR spectroscopy. The PEO grafting-density onto PSZ by hydrosilylation increases with a reduction of the S-H/allyl ratio and a decrease of the PEO chain-length. The PEO-graft-PSZ (PSZ-PEO) hybrid coatings, which can be used to prevent the adhesion of marine bacteria on surfaces, were applied by moisture curing at room temperature. The anti-adhesion performance, and thus the anti-fouling activity, of the coatings against three marine bacteria species, Clostridium sp. SR1, Neisseria sp. LC1 and Neisseria sp. SC1, was examined. The anti-fouling activity of the coatings depends on the grafting density and the chain length of PEO. The shortest PEO(350 g/mol)-graft-PSZ with the highest graft density was found to have the best anti-fouling activity. As the density of grafted PEO(750 g/mol) and PEO(2000 g/mol) chains onto the PSZ surface is approximately equal, the relative effectiveness of these two types of PEO is controlled by the length of the PEO chain. The PEO(2000 g/mol)-graft-PSZ coatings are more efficient than the PEO(750 g/mol)-graft-PSZ coatings for the bacterial anti-adhesion

Higher chromatic rendition with Cr3+-doped yellow Y3Al5O12:Ce3+ for double-layer remote phosphor white-light-emitting diodes

Remote phosphor designs of white-light-emitting diodes (WLEDs) have been recognized for their high thermal stability and excellent luminous efficiency but not for the chromatic rendering. The study presents an approach for the remote phosphor structure to overcome the low-color-rendering issue by enriching its red-light spectral intensity through co-doping Cr3+ and Ce3+ ions into the yellow  Y3Al5O12 (YAG) phosphor compound. This ion co-doping process probably enhances emission spectra in the far-red range because of the energy transfer of the integrated ions: Ce3+ Cr3+. Additionally, the luminescence and color properties of the phosphor layer significantly depend on the doped concentration of the Cr3+ ion. Here, with 0.008% Cr3+ in the phosphor composite, either internal or external quantum performances of the dual-layer WLED light are enhanced, which achieved the number of 58.9% and 46.7%, respectively. The color rendering index (CRI) would also be higher if Cr3+ is added, about 77.9, compared to the CRI of 63.2 when using the original  YAG:Ce3+ phosphor layer

Effects of Teacher’ Feedback on Learners: Perspectives of English Majors at a Private University

Feedback is claimed to be a great contributor to learners’ academic achievements. However, in real-life classrooms, teachers’ feedback-giving practices do not always match learners’ expectations, resulting in adverse effects on learners. This study investigates the frequency, the timing, the manners that the teachers of English majors at Nguyen Tat Thanh University (EFL teachers at NTTU henceforth) delivered feedback on their students’ oral performance, their feedback contents and the influence of their feedback-giving practices on the students’ learning motivation and language achievements. The study adopted a mixed methods research design. The quantitative data were collected from the observation with 10 classes delivered by 10 EFL teachers at NTTU and from the interviews with 30 students attending the 10 classes observed with 3 students per class. The interviews also provided targeted qualitative data. The findings show that not all the teachers recognized the importance of feedback. Some ignored or gave insufficient feedback during teacher-student interactions. In some cases, the teachers’ feedback was too general to help students make any improvements in their performance. Some even provided feedback in a way that negatively influenced the students’ psychology and learning motivation. The findings also reveal the students’ expectations for frequent, timely, constructive feedback given in encouraging manners. The study finally makes some recommendations regarding feedback giving for NTTU teachers

The Endo-α(1,4) Specific Fucoidanase Fhf2 From Formosa haliotis Releases Highly Sulfated Fucoidan Oligosaccharides

Fucoidanases are endo-fucoidanases (also known as endo-fucanases) that catalyze hydrolysis of α-glycosidic linkages in fucoidans, a family of sulfated fucose-rich polysaccharides primarily found in the cell walls of brown seaweeds. Fucoidanases are promising tools for producing bioactive fucoidan oligosaccharides for a range of biomedical applications. High sulfation degree has been linked to high bioactivity of fucoidans. In this study, a novel fucoidanase, Fhf2, was identified in the genome of the aerobic, Gram-negative marine bacterium Formosa haliotis. Fhf2 was found to share sequence similarity to known endo-α(1,4)-fucoidanases (EC 3.2.1.212) from glycoside hydrolase family 107. A C-terminal deletion mutant Fhf2∆484, devoid of 484 amino acids at the C-terminus, with a molecular weight of approximately 46 kDa, was constructed and found to be more stable than the full-length Fhf2 protein. Fhf2∆484 showed endo-fucoidanase activity on fucoidans from different seaweed species including Fucus evanescens, Fucus vesiculosus, Sargassum mcclurei, and Sargassum polycystum. The highest activity was observed on fucoidan from F. evanescens. The Fhf2∆484 enzyme was active at 20–45°C and at pH 6–9 and had optimal activity at 37°C and pH 8. Additionally, Fhf2∆484 was found to be calcium-dependent. NMR analysis showed that Fhf2∆484 catalyzed hydrolysis of α(1,4) linkages between L-fucosyl moieties sulfated on C2 (similar to Fhf1 from Formosa haliotis), but Fhf2∆484 in addition released oligosaccharides containing a substantial amount of 2,4-disulfated fucose residues. The data thus suggest that the Fhf2∆484 enzyme could be a valuable candidate for producing highly sulfated oligosaccharides applicable for fucoidan bioactivity investigations

Experiência de aprendizagem de estudantes de enfermagem na prevenção e controlo de infeções associadas aos cuidados de saúde (PC-IACS) em países asiáticos: um estudo qualitativo exploratório

Background: Healthcare-associated infection prevention and control (HAI-PC) education programs in Asian countries seem limited and require improvement and support. Objective: This study explored students’ learning experiences with HAI-PC education programs in Asian countries (two Vietnamese and two Cambodian universities) to support a pedagogical model in HAI-PC. Method: A qualitative exploratory study design was employed, and inductive content analysis was conducted. Students were selected to participate in the focus group to investigate their experiences with HAI-PC using five structured questions. There were 48 nursing students in total from four universities, 28 from 2 universities in Cambodia, and 20 from two universities in Vietnam. Results: The summary results gained from the four universities were synthesized by grouping them into sub-categories and four primary categories, which were students’ HAI-PC competence, students’ current learning methods in HAI-PC Education, the HAI-PC teaching and learning environment, students’ capacity, and entrepreneurial skills in HAI-PC development. Conclusion: This study revealed evidence to improve nursing education in HAI-PC in Asian countries. The new learning method of the simulation scenario and the model fascinated the students; they were happy and more confident about their future careers in practicing HAI-PC skills in their clinical practicum and hospital practice. The current HAI-PC education faces issues related to education and healthcare systems in Asian countries, highlighting the need for improvement.Enquadramento: Os programas de educação em prevenção e controlo de infeções associadas aos cuidados de saúde (PC-IAS) em países asiáticos parecem ser limitados e necessitam de melhorias e apoio. Objetivo: Este estudo explorou as experiências de aprendizagem dos estudantes com programas de educação em PC-IAS em países asiáticos (duas universidades vietnamitas e duas universidades cambojanas) para apoiar um modelo pedagógico em PC-IAS. Método: Foi utilizado um desenho de estudo exploratório qualitativo, e foi realizada uma análise de conteúdo indutiva. Os estudantes foram selecionados para participar no grupo focal para investigar as suas experiências com PC-IAS usando cinco perguntas estruturadas. No total, participaram 48 estudantes de enfermagem de quatro universidades, sendo 28 de duas universidades no Camboja e 20 de duas universidades no Vietname. Resultados: Os resultados resumidos das quatro universidades foram sintetizados agrupando-os em subcategorias e quatro categorias principais, que eram competência dos estudantes em PC-IAS, métodos de aprendizagem atuais dos estudantes em Educação em PC-IAS, ambiente de ensino e aprendizagem em PC-IAS, capacidade dos estudantes e habilidades empreendedoras no desenvolvimento de PC-IAS. Conclusão: Este estudo revelou evidências para melhorar a educação em enfermagem em PC-IAS em países asiáticos. O novo método de aprendizagem do cenário de simulação e o modelo cativaram os estudantes; eles ficaram felizes e mais confiantes em relação às suas futuras carreiras na prática de habilidades em PC-IAS no estágio clínico e na prática hospitalar. A educação atual em PC-IAS enfrenta questões relacionadas aos sistemas de educação e saúde em países asiáticos, destacando a necessidade de melhorias

Simulação como método de ensino na formação em enfermagem na prevenção e controlo de infeções associadas aos cuidados de saúde em países asiáticos: um estudo qualitativo

Background: Applying simulation for nursing education, especially in healthcare-associated infection prevention and control (HAI-PC) in developing countries has limited evidence. The study was conducted to explore educators’ perceptions of simulation as a teaching method for nursing education in HAI-PC in two Vietnamese and two Cambodian universities. Methods: An exploratory qualitative design was applied. A focus group of 37 educators from four universities was conducted for data collection. Inductive and deductive qualitative content analysis was applied in analysing the data. Results: The core category was constructed to reflect educators’ perception of scenario-based simulation (SBS) as a teaching method for nursing education in HAI prevention and control. This main category included three subcategories: (i) enhancing nursing competence; (ii) preparing students for simulation; and [1] promoting simulation pedagogy competence. Conclusions: The findings identified the importance and benefits of applying simulation as a teaching method in nursing education. Additionally, it emphasized the necessity of enhancing knowledge associated with HAIs and providing additional training on simulation for educators to improve the quality of conducting simulations.Enquadramento: A aplicação da simulação no ensino de enfermagem, especialmente na prevenção e controlo de infeções associadas aos cuidados de saúde (IACS), em países em desenvolvimento, tem evidências limitadas. O estudo foi conduzido para explorar as perceções dos educadores sobre a simulação como método de ensino para a formação em enfermagem na prevenção e controlo de IACS em duas universidades vietnamitas e duas universidades cambojanas. Métodos: Foi aplicado um desenho qualitativo exploratório. Um grupo de discussão com 37 educadores de quatro universidades foi conduzido para a recolha de dados. A análise qualitativa de conteúdo indutiva e dedutiva foi aplicada na análise dos dados. Resultados: A categoria central foi construída para refletir a perceção dos educadores sobre a simulação baseada em cenários (SBC) como método de ensino para a formação em enfermagem na prevenção e controlo de IACS. Esta categoria principal incluiu três subcategorias: (i) aprimoramento da competência em enfermagem; (ii) preparação dos estudantes para a simulação; e [1] promoção da competência em pedagogia de simulação. Conclusões: Os resultados identificaram a importância e benefícios da aplicação da simulação como método de ensino na formação em enfermagem. Além disso, enfatizou a necessidade de aprimorar o conhecimento associado às ICACS e fornecer treinamento adicional sobre simulação para educadores, visando melhorar a qualidade da condução das simulações

Experiências do estudante de enfermagem na aprendizagem da prevenção e controlo de IACS em países asiáticos através do uso de simulação baseada em cenários: um estudo qualitativo exploratório

Background: Healthcare-associated infections (HAIs) have posed a major threat to both patients and to the safety healthcare personnel worldwide. According to the World Health Organization, 10% of hospitalized patients are affected by HAIs worldwide. Objective: The objective of this study was to explore the experiences of nursing students in learning HAIs prevention and control by the application of the scenario-based simulation pedagogy now in use in two Vietnamese and two Cambodian universities. Methods: A qualitative study was conducted among 160 nursing students from 2 Cambodian universities and 2 Vietnamese universities, and by using the purposive-sampling method. The data were collected through a focus group discussion and analyzed by the Graneheim and Lundman method (Graneheim & Lundman, 2004). Results: Two themes and six categories were generated. 1) First theme: factors for enhancing student learning on the prevention and control of HAIs by use of scenario-based simulation; and 2) Second theme: factors hindering students learning on HAI prevention and control by use of scenario-based simulation. Conclusion: The findings showed that SBS is an effective learning method for nursing students that can be applied to enhance the quality of nursing education in the Asian countries as SBS not only improves the clinical skills, but also the soft skills of nursing students. However, the effective outcomes and impacts can only be achieved in the context with the appropriate learning materials and equipment, simulation facilities and the instructors with pedagogical skills.Enquadramento: As infeções associadas a cuidados de saúde (IACS) têm representado uma grande ameaça tanto para os pacientes quanto para a segurança dos profissionais de saúde em todo o mundo. De acordo com a Organização Mundial da Saúde, 10% dos pacientes hospitalizados são afetados por IACS em todo o mundo. Objetivo: O objetivo deste estudo foi explorar as experiências dos estudantes de enfermagem na aprendizagem da prevenção e controlo de IACS através da aplicação da pedagogia de simulação baseada em cenários, atualmente em uso em duas universidades vietnamitas e duas universidades cambojanas. Métodos: Um estudo qualitativo foi conduzido entre 160 estudantes de enfermagem de duas universidades cambojanas e duas universidades vietnamitas, utilizando o método de amostragem propositada. Os dados foram recolhidos através de uma discussão em grupo focal e analisados pelo método de Graneheim e Lundman (Graneheim & Lundman, 2004). Resultados: Dois temas e seis categorias foram gerados. 1) Primeiro tema: fatores que contribuem para a aprendizagem dos estudantes na prevenção e controlo de IACS pelo uso de simulação baseada em cenários; e 2) Segundo tema: fatores que impedem a aprendizagem dos estudantes na prevenção e controlo de IACS pelo uso de simulação baseada em cenários (SBC). Conclusão: Os resultados demonstraram que a SBC é um método de aprendizagem eficaz para estudantes de enfermagem que pode ser aplicado para melhorar a qualidade da educação em enfermagem nos países asiáticos, uma vez que a SBC não só melhora as habilidades clínicas, mas também as habilidades interpessoais dos estudantes de enfermagem. No entanto, os resultados e impactos efetivos só podem ser alcançados no contexto com os materiais e equipamentos de aprendizagem apropriados, instalações de simulação e instrutores com habilidades pedagógicas

SIMULATION AS A TEACHING METHOD FOR NURSING EDUCATION IN HEALTHCARE-ASSOCIATED INFECTION PREVENTION AND CONTROL IN ASIAN COUNTRIES: A QUALITATIVE STUDY

BACKGROUND: Applying simulation for nursing education, especially in healthcare-associated infection prevention and control (HAI-PC) in developing countries has limited evidence. The study was conducted to explore educators’ perceptions of simulation as a teaching method for nursing education in HAI-PC in two Vietnamese and two Cambodian universities. METHODS: An exploratory qualitative design was applied. A focus group of 37 educators from four universities was conducted for data collection. Inductive and deductive qualitative content analysis was applied in analysing the data. RESULTS: The core category was constructed to reflect educators’ perception of scenario-based simulation (SBS) as a teaching method for nursing education in HAI prevention and control. This main category included three subcategories: (i) enhancing nursing competence; (ii) preparing students for simulation; and [1] promoting simulation pedagogy competence. CONCLUSIONS: The findings identified the importance and benefits of applying simulation as a teaching method in nursing education. Additionally, it emphasized the necessity of enhancing knowledge associated with HAIs and providing additional training on simulation for educators to improve the quality of conducting simulations

EXPERIENCES OF THE NURSING STUDENT IN LEARNING HAI PREVENTION AND CONTROL IN ASIAN COUNTRIES THROUGH THE USE OF SCENARIO-BASED SIMULATION: AN EXPLORATIVE QUALITATIVE STUDY

BACKGROUND: Healthcare-associated infections (HAIs) have posed a major threat to both patients and to the safety healthcare personnel worldwide. According to the World Health Organization, 10% of hospitalized patients are affected by HAIs worldwide. OBJECTIVE: The objective of this study was to explore the experiences of nursing students in learning HAIs prevention and control by the application of the scenario-based simulation pedagogy now in use in two Vietnamese and two Cambodian universities. METHODS: A qualitative study was conducted among 160 nursing students from 2 Cambodian universities and 2 Vietnamese universities, and by using the purposive-sampling method. The data were collected through a focus group discussion and analyzed by the Graneheim and Lundman method (Graneheim & Lundman, 2004). RESULTS: Two themes and six categories were generated. 1) First theme: factors for enhancing student learning on the prevention and control of HAIs by use of scenario-based simulation; and 2) Second theme: factors hindering students learning on HAI prevention and control by use of scenario-based simulation. CONCLUSION: The findings showed that SBS is an effective learning method for nursing students that can be applied to enhance the quality of nursing education in the Asian countries as SBS not only improves the clinical skills, but also the soft skills of nursing students. However, the effective outcomes and impacts can only be achieved in the context with the appropriate learning materials and equipment, simulation facilities and the instructors with pedagogical skills

Revêtements polysilazane à activités antibactériennes

The objective of this work was to develop new polysilazane (PSZ) coatings which can inhibit the adhesion of marine bacteria. Two chemical strategies have been investigated: the grafting of poly(ethylene oxide) (POE) (350, 750, 2000 g/mol) on PSZ chains by hydrosilylation and the association of copper compounds with a pyrolized vinylsilazane matrix. The optimum conditions for grafting POE were defined to have a high selectivity toward olefin hydrosilylation. Crosslinking of POE-graft-PSZ was performed by moisture curing at room temperature. The main reactions occuring during curing are hydrolysis-condensation reactions of alkoxysilane, Si-H and Si-N functionalities. 29Si NMR in the solid state revealed the formation of a large amount of T3 Si [(RSi(OSi)3)]. The crystallization of short POE chains (350 g/mol) was found to be totally inhibited whereas long POE grafts (750 and 2000 g/mol) are still able to crystallize. The hydrophilic-hydrophobic properties and the antibactericidal activity of films with different graft density and POE chain length were studied. The POE (350 g/mol)-graft-PSZ with the greatest graft density were found to have the best antibactericidal activity. The incorporation of copper compounds in a pyrolized oligovinylsilazane was performed using copper acetylacetonate as a copper source. Pyrolysis was conducted in air or in Argon atmosphere. Identification of the copper phases was performed by XRD analysis. The reductive environment during thermal degradation of PSZ was found to favour the formation of copper (0) and copper (I) species relative to copper (II) species. The study of bacterial adhesion suggested that CuO and Cu2O crystals were more effective against bacterial adhesion than copper metal.Ce travail porte sur l’étude de revêtements polysilazane (PSZ) élaborés dans le but d’inhiber l’adhésion des bactéries marines. Deux stratégies ont été étudiées : le greffage de chaînes poly(oxyde d’éthylène) (POE) (350, 750 ou 2000 g/mol) sur les chaînes PSZ par réactions d’hydrosilylation d’une part, et l’incorporation de composés du cuivre dans un film céramique issu de la pyrolyse d’un précurseur PSZ, d’autre part. Les conditions optimales de synthèse des PSZ greffés POE ont été définies afin de limiter notamment la réaction d’isomérisation de l’allyl-POE. La réticulation des PSZ greffés POE est alors effectuée par voie humide à température ambiante et procède par hydrolyse-condensation des fonctions alcoxysilane, SiH et SiN du précurseur PSZ. La prédominance des Si de type T3 (RSi(OSi)3) a été mise évidence par spectrométrie RMN du 29Si à l’état solide. La cristallisation des chaînes courtes de POE (350 g/mol) est totalement inhibée alors que l’aptitude des chaînes longues POE (750 et 2000 g/mol) à cristalliser est préservée. Le caractère hydrophile-hydrophobe et la capacité des films à inhiber l’adhésion bactérienne a été étudiée sur des revêtements à densités de greffons et à longueur de chaînes POE différentes. Les PSZs greffés POE 350g/mol avec un taux de greffage maximal conduisent à l’activité bactérienne la plus élevée de l’ensemble des revêtements étudiés.Les films céramiques incorporant du cuivre ont été préparés par pyrolyse d’un oligovinylsilazane en présence d’acétylacétonate de cuivre II sous atmosphère oxydante ou non oxydante. L’identification des phases des composés du cuivre a été effectuée par analyse DRX. L’environnement réducteur généré lors de la pyrolyse du PSZ favorise la formation d’espèces de cuivre (0) et cuivre (I) au détriment de cuivre (II). Les études bactériennes suggèrent que les cristaux CuO et Cu2O sont plus efficaces que le cuivre métal pour lutter contre l’adhésion bactérienne